The IDC report on enterprise use of smartphones notes that businesses are buying iPhones "in droves," though Android-based devices top --- by far -- the list of smartphones purchased directly by workers.

IDC separates these business-bought (or "corporate liable") and employee-purchased (or "employee liable") smartphones from those bought by the much larger consumer category.

IDC projects that for all of this year, consumer shipments of Android smartphones will reach 351.9 million, "employee liable" shipments will be 87.7 million and "corporate liable" shipments will total 15.1 million.

By contrast, Apple will ship 78.6 million iOS-based iPhones to consumers, 37.1 million to workers and 31.1 million to companies.

Combined, the "corporate liable" shipments of iPhones and Android-based smartphones will outdistance similar BlackBerry sales for the first time.

Employee liable shipments of the Research in Motion BlackBerry in 2012 will reach 5.2 million, while consumer BlackBerry shipments will total 14.8 million, projects IDC.

The iPhone will top the "corporate liable" smartphone shipment list trough 2016, when it reaches 68.9 million shipments, IDC said in its forecast.

BlackBerry led in "corporate liable" smartphone shipments in 2011 with 22.4 million.

"BlackBerry continues to be the gold standard for security," IDC said, but added that reduced consumer and developer interest "hinders its viability going forward."

IDC analysts said that the future of Android has the "opposite problem" of that facing the BlackBerry. The Google-built and open source operating system has a large developer community but a fragmented device ecosystem and "more gaps in security than many organizations are comfortable with," IDC said.

Meanwhile, Apple's popularity with consumers and a tight security model "have made it a win-win for enterprise use," IDC said. The IDC report notes that Apple's strict rules about application deployment and management "can create frustration."

IDC called Windows Phone a "dark horse" and predicts that few companies will be adopting the new Microsoft platform soon.

IDC forecast that global smartphone shipments across all categories for 2011 were 494.2 million. The report projects that the number of smartphone shipments is expected to reach 1.25 billion in 2016.